Continuous-water-tube flash-type steam generator



Oct. 4 1927.

CONTINUOUS 1,644,078 J. H. O'NEILL ET AL WATER TUBE FLASH TYPE STEAM GENERATOR Filed July 24, 1922 3 Sheets-Sheet 1 IN V EN TORS.

4,1921 .1. H. ONEILL ET AL CONTINUOUS WATER'TUBE FLASH TYPE STEAM GENERATOR Filed July 24, 1922 3 Sheets-Sheet 2 9% x4 w m Patented Oct. 4, 1927.

' UNITED STA JOHN HUGH ONEILL, 0F

' Application filed Ju1y'24,

The object of our invention is to produce a continuous water tube, flash type steam generator of high thermal efliciency and of great reliability and durability. A further object 'of our invention is to obtain such a generator of the lightest weight per horsepower. A' further object of our invention is to make a steamgenerator of this type which can be built readily in'any desired size even up into thousands of horsepower.

Heretofore the coils-in continuous water tube, flash type steam generators have been. spaced apart and held in place by solid straps or rods of metal which-rapidly become oxidized and eaten or burned away due to their exposure to the hot combustion products, hence frequent renewal of such holding means has been necessary. To prevent this deterioration, we so bend the water I tubes themselves that they form the spacing and tying and'holding elements. To further secure the permanent location of one coil in relation to other coils of the water tubes, where they cross one another they may be welded one to the other by any of the autogenous welding methods such as oxyacetylene torch or electric welder; ,Such construction makes it unnecessary to have in the path of the combustion products, metal members which are not cooled and protected by an internal circulation of water or steam, thus adding greatly to the length of life and reliability of the generator, and as all the metal in the path of the combustion products in this arrangement is useful in transferring heat to the water or steam, great saving in weight is accomplished. On the outside of the coilsthere may be binding and supporting members of solid metal which are-partially out of the path of the combustion products and such members maybe cooled by conduction through welds to the tube coils, thus'keeping the support members from becoming very hot which prevents such rapid deterioration as would otherwise follow from the high temperatures. 4

v'In order to more clearly set forth our invention we herewith describe the design of same and append drawings in which: I Fig. 1 is a diagrammatic, longitudinal cross section of our continuous watertube flash type team generator,

' Fig. 52 is a partial diagrammatie trans: verse section of same.

SPRINGFIELD, MISSOURI, AND WARD LEATHERS, or nnwon'rn, NEW JERSEY. I

CONTINUOITS-WATERQTUBE ,FLASH-TYPE ,s'rnA vr GENERATOR.

1e22, Serial No. 576,984.

' Fig. 3 is a diagrammatic cross section of Fig. 2 on line 38.

Fig. 4 is a detail of a special water tube coil protecting the central refractory core of the generator.

Fig.5 is a diagrammatic cross section of Fig. 4 on line-55.

Fig. 6 is a sectional view of a protector made of a refractory for this special coil.

In Fig. 1, -1 is a water distributor or meter, which divides the feedwater received through pipe2 from a boiler feed pump not shown and distributes it, in this. I

case, in four equal quantities one to-each of the four tubes 3, 4, 5 and. 6 which I run throughthe generatorv as four continuous tubes until united in or joined to the steam header 7 as by the unions 8 and 9, the other two unions not being visible in this view. The tubes 3, 4:, 5 and 6 are carried into the path of the combustion products at 10 where the combustionproducts leave thegenerator. The tubes are led in an approximately radial direction to'the central part of: the

generator where they are bent through a short arc about a central refractory core 11 and at the same time upward as in a helix about the core 11 until each is on a level above the incoming radial portion, at which, point, 12, the four tubes are'bent inparallel concentric spirals out-to the periphery of the generator coils. At this point, 13, they are again led'in, in an approximately radial'direction toward the center to a point tangent to the core 11, then the portion of arc in an upward helix is repeated and the spiral pancake also, as is moreclearly shown in Figs. 2 and 3. [In this Way the tubes are bent alternately in a radial direction and then in a spiral pancake, repeated as often as desired, and when welded to'each other, as shown at 14, and to the outside support members, as at 15, make'a very compact and secure arrangement capable of withstanding the vi bration and shock incidentalto use on an automotive device; Suchradials and pancakes are repeated, with the feed water traveling through he tubes toward the combustion chamber, and in counterflow to the products of combustion, to the point 16 at which point the -modification of the couriterflow takes place. i 1 *Tiiegwateawhicli has been heated approxi merely to the temperature agreeifi with the pressure carried, is tubes.

17 andv unions 18 to the second section or zone, located next to thecombustionchamber. The tubes 19 continue the radial arrangement which is alternated with the spiral-pancakes through which thewater and steam is led in a resumed counterflow 'toward the combustionchamber until at20 the tubes are bent into a special coil, (shown more fully in Figs. 4, 5 and 6) which is for may be formed by bending the four tubes gas into parallel helices otparallel sides-for a partio t :thebeehiyeand into tapering sides at theLupper portion until the water tube Wall rot-the combustion chamberends at 22. These coils of tour; parallel water tubes from 19 tor20 and from 21 to 22;form the second section or Zone in which the water is evap- T orated to steam that is nearly dry. These coilslareexposed to the combustion products while the combustion takes place, and where the temperature in the gases is maximum,-but because of the water and Wet stea-m circulating through them they are protected by the rapid evaporization from being injured by the extremely'hot gases, and because of the great temperature difference a between vthe gases and'the coils 1(250O to 3500 F. in the gases andnot' to excee' ds700 F. int-he coils for steam at 3000 pounds pressure) the heat transfer is extremely rapid,:probably at the rate of pounds cl? water or more evaporatedper'sq. foot of fireiheating surface, per hour. This rapid evaporation is necessary in the attainment of light weight in the generator, and it is accomplished without rapid'deterioration ofthe tubes or danger of overheating them, by means of the modified counterflow.

At 23, unions connect tubes 24 whichdead the steam to unions 25 which connect Ito radials '26 from which point radials and spiralpancakes again alternate and through which thesteam is again led in resumed counterflow toward the combustion chamber to the point 27 at-which the dried and superheated steam isconnected tothe steam: header Tby'the unions 8 and 9 and two more unions not shown, in thisyiew.

"From point26 to point 27 is the third section-o'r zone oft-he modified coun'tertlow. In this section the steam is dried. and superheated in tubes exposed-to the combustion products cooled to approximately 1500 -to 1800 F. at'the point 27 byfhaving passed over the tubes from 20 to .71 9. Because of the small temperature difference &00 to 5500 ?F between the combustion products .and the 5 tubes and containedsteam, consider ableivariation in the flowofisteammay take placewithout 'damageito {the tubes from overheating. e I

At QBisthe pipethrough which is pumped 1 01--- forced by other controllable" means, the oil i'uel from a source not shown.

V The oil 1 is vaporized in the tubecoilflfl which forms a portion otft-he combustion chamber wall ,ill'lChl'llfly beexposedto'thedirect heat of the combustion, as shown, or may have some coils of ,th-e'steam tubes 4 .22 between the coil-29 and the-,soui'ce ofiheat. From the coill 29 the oil vapor is delivered. I at 30;-to the annular chamber 31 from which it issues, throughthe s1nalltubesL3Q ;and the-holes 53 g-at right,

angles to the air;whichenters thecombustion chamber throughfthe round portoi i formed;-by-; theannular chamber 31. wl n this way; ,a: very intimate; mixture is; made of the Oil 35 Yan s ndv hec mb s i s nper ies 1 r. At f 35 air;- torsupporting combustion is supplied irom a blower and measuring des The waste combustion prod-- ieenotshowu. nets whach, hare, passed over the water coils and the incoming-fair iiowin oppo ite-dime tions; through altennate chanhels diorinegd, of

suitable unetal suchwasl alul'ninium, so that the heat'i'rom thewaste gasesels;transferred through the metal walls to the nconnngair,

warm i ng; the air to -approximately 25 0 F.

while cooling the gasesQ-to 30,0"v ,to 350 The incoming air,- irom the distributing- I of; the airandi because the oil fuel 18,111 hot vaporized state, the ,combustion vigorous and the mesulting temperature is about 3500 F..;where an approximately 10% excess of air dssupplied. Theproducts-of combustion passdownward "from ,the com bust-ion chamber 42' flowing between the tubes 'of the pancakesendradials from 20 to :19 of the second section, Efrom127-to26J of the third sect-i0 :frem r16, tolQ pt t rs section, then,- as shown bythe solid arrows ig through channels alternatetothe incoming 'air channels to collector 4A and exhaust fl,ue:4;5.; Theincoming air andl-exhaustsgases are guided in connterflow-by' {the 1 directing partitions 46 which are the same inieach channel. At 4'1 is-shown a binding {and sup- :p i siwrangle i Q rWh may b welded o th sa s,cen inuqu lyr r m bottom t0 top, or in lensthsitoor sp l v h sections fiO thatth sec ens entle-assembled separately and tl enjoined intothecomplete eene t tq es is ll wn b the 13 d t more clearly in v At 48 the inner sheetof wall 40 is shown. This sheet steel member is welded to the support members 47 and makes with the outside sheet 49 an airtight casing around the generator. The space between inside sheet 48 and outside sheet 49 of'wall 40 is filled with suitable heat insulation such as magnesia or asbestos. At 50 is shown a solid refractory such as refractory brick, which may be imflamed oil saturated waste or permanent electric spark gap and gasoline and air supply.

In Fig. 1 was illustrated a steam generator suitable for standing vertically with the combustion chamber at the top, wherein the water would always be trapped or drained to the bottom of each section, with a minimum of tendencyto fiow toward the steam outlet. It could also be used horizontally, in which case each coil would form a trap. This form of generator is suitable for large and quite steady output.

In Fig. 2, 49 is the outer sheet of wall 40, and 48 the inner sheet. 48 is joined to support member 47 by welding. 53 and 53 are hand hole covers which may be provided for convenientlycl'osing or opening the unions 8 as on header 7 or on other joints as union 18 on radial 19. Fig. 2 is to more clearly show how the radials are carried in from the periphery as at 54 and pass around the core 11 as at 55 and then are bent spirally outward as at 56 and out through sheet 48 as at 57 to accommodate a union or the tube may be bent inwardly again as a radial as at 58.

Joints 51 are p Fig. 3 illustrates the change of level of the radial 54 in passing into the spiral at 55 and 56 and in passing from pancake to radial as at 58.

Figs. 4 and 5 illustrate more clearly the special coil at 20 wherein the four tubes are brought repeatedly over the central core and are welded together in the centeras shown at 59. This is useful as it is diflicult to obtain a refractory for the core 11 which would endure the hot blast at 3500 F. without some water cooled protection.-

Fig. 6 shows a refractory'cap 60 which may be held by metal spikes welded to 59 and used as a protection to the tubes against the hot blast of the combustion products. This protector cap may or may not be used, depending on the size and serviceof the generator, and may be of any size or shape and also function as a hot surface combustion member, which is partially cooled by contact with the tubes of coil 20, which partial cooling will enable the refractory to stand up under intense heat of the gases.

Naturally there are many combinations possible of the improvements described in our steam generator, and all these various combinations fall within the spirit of our invention.

lVe claim In a flash type steam generator, a plurality of continuous water and steam conduits, said conduits being arranged in parallel relation in alternate layers of spiral coils and radially disposed portions of said conduits, said-conduits being adapted to form supports, spacers and tying members in one layer for the other layer, said conduits in one layer crossing said conduits in the next adjoining layer, said conduits being autogenously welded together at said crossings.

JOHN HUGH ONEILL. WARD LEATHERS. 

